Parse CSR: The Online CSR Parser for SSL/TLS Professionals

Why Parse a Certificate Signing Request (CSR)?

Before you can obtain an SSL/TLS certificate from a Certificate Authority (CA) like Let's Encrypt, DigiCert, or Sectigo, you must generate a Certificate Signing Request (CSR). A CSR is an encoded block of text (typically in PEM format) that contains your public key and your organization's identifying information (the Subject).

Because a CSR is Base64-encoded, it is completely unreadable to the human eye. If you generate a CSR using OpenSSL or a control panel but make a typo in your domain name, your final SSL certificate will be invalid.

Our online CSR Parser instantly decodes your PKCS#10 formatted request. It allows you to verify critical details—such as the Common Name (CN), Organization (O), Locality (L), and Subject Alternative Names (SANs)—before you submit it to a CA, saving you time and preventing costly certificate reissuance.

Engineered for Security: 100% Client-Side Decoding

Even though a CSR only contains public information (it does not contain your private key), practicing strong Operational Security (OPSEC) means you should never casually upload cryptographic files to random servers. We never transmit, save, or log your CSR text or your domain information. The ASN.1 parsing engine runs completely offline within your web browser's local sandbox. Because no data is sent to a remote API, the decoding process happens instantaneously.

How to Decode a CSR Online?

Verifying your Certificate Signing Request is fast and simple:

1. Paste Your CSR: Copy your entire CSR text, including the -----BEGIN CERTIFICATE REQUEST----- and -----END CERTIFICATE REQUEST----- header and footer tags, and paste it into the input box.

2. Instant Parsing: Our local JavaScript engine immediately decodes the Base64/ASN.1 structure.

3. Verify the Data: The tool will automatically display the parsed fields:

   Common Name (CN): Ensure the primary domain name is spelled correctly (e.g., www.example.com).

   Subject Alternative Names (SANs): Verify that all additional domains or subdomains are listed if you are applying for a Multi-Domain/UCC certificate.

   Organization Details: Check your Company Name, City, State, and Country codes.

   Public Key Info: Confirms the key algorithm (e.g., RSA or ECDSA) and key size (e.g., 2048-bit or 4096-bit).

Frequently Asked Questions (FAQ)

• Q: Does my CSR contain my Private Key?

  A: No. A properly generated CSR strictly contains your Public Key and your identity information. Your Private Key must remain strictly on your server and should never be shared with anyone, not even your Certificate Authority. (Note: If your file starts with BEGIN PRIVATE KEY, do NOT paste it here. Keep it safe!)

• Q: How can I view a CSR using the OpenSSL command line instead?

  A: If you prefer using terminal commands over an online GUI, you can easily parse and view a CSR locally using OpenSSL. Simply run the following command: openssl req -in your_domain.csr -noout -text

• Q: Why does my CSR look like a random block of characters?

  A: Standard CSR files are encoded using the ASN.1 standard according to the PKCS#10 specification, and then Base64-encoded into PEM format so they can be easily copied and pasted in emails or web forms. Our parser simply reverses this encoding to show you the readable text.

• Q: What happens if the CSR Parser shows an "Invalid Format" error?

  A: This usually means the pasted text is missing the required --BEGIN-- and --END-- headers, or the Base64 structure has been corrupted by hidden spaces or line breaks. Ensure you have copied the raw text exactly as it was generated.